Sass is probably the de facto for styling web applications today. I think many designers prefer Sass for its simple and powerful variables along with some other cool features. With variables, defining color schemes for your awesome web design is as easy as pie. It helps in re-using colors through out the project resulting in maintainable and clean code.

In our sass projects, we have to work with different color shades and variables. Defining color shades with hex (or rgb) as above just does not feel intuitive. So, we can use HSL for simpler color variables. Once you get hang of hsl, it is kind of difficult to get back to hex and rgb values.